Significantly increased requirements regarding the environmental compatibility of combustion engines require more specific measures for reductions in consumption and emissions. Every modification to the...

The development of new propulsion systems for future vehicle generations is, among other aspects, characterized by: stringent legislative requirements, increasing system complexity and variety,
further...

The New Yanmar TNV Engine Series for Future Off-Road Machinery

17. October 2014 | Engineering Service

Close to customer demands: Yanmar, with strong FEV support has developed the new TNV series engine that offers a power output range of 19 to 56 kW. As a result of the development cooperation, the TNV is a powerful, quiet, and highly durable engine series with improved fuel consumption and it complies with strict Tier 4 emission regulations. Yanmar’s advanced combustion technology, featuring a common rail injection system and cooled exhaust gas recirculation (EGR) is combined with model-based control strategies that are leveraged to achieve excellent engine performance under all operating conditions. In addition, an exhaust aftertreatment system that includes a Diesel particulate filter (DPF) has been adopted for cleaner exhaust gas emission, making it a truly “green” engine.

The engine management system employs Yanmar’s unique software to assure best engine performance by automatically adjusting engine operating parameters. The EGR rate is controlled on the basis of physical models without using an air mass flow sensor, thus enabling compensation of environmental impacts (such as altitude), varying backpressure (due to DPF loading) or intake piping geometry. This leads to benefits for real-world operation as well as reduced calibration effort.

Safe compliance with Tier 4 emission limits

Compared to previous EPA Tier 3 engines, the engine family’s steady-state NOx+NMHC emissions are significantly reduced by using common rail technology and cooled EGR. PM emissions are drastically reduced by the DPF and low emissions during transient operation are further ensured by the engine control software. As a result, the Tier 4 emission limits can be safely achieved in both steady-state (C1) and transient (NRTC) test cycles as well as the not-to-exceed (NTE) engine map area.

3-step regeneration strategy

The unique model allows the amount of PM accumulated in the soot filter to be precisely estimated for a better regeneration schedule and the integrated engine and aftertreatment management system helps to achieve reliable DPF regeneration for all relevant off-road machinery application operating cycles and boundary conditions. To achieve these goals, a unique 3-step regeneration strategy without changing engine operating feeling is used: • “Assist regeneration”: The first step of DPF regeneration with intermediate temperature is initiated when the amount of PM reaches a predefined limit. • “Reset regeneration“: The second step of DPF regeneration with higher exhaust temperature is activated when a pre-defined amount of operating time is reached. • “Unscheduled stationary regeneration”: The third step will be requested for safety reasons, in the case that “assist regeneration” and “reset regeneration” cannot be successfully achieved and PM loading exceeds a pre-defined limit.